Chemical Space Charting of Different Parts of Inula nervosa Wall.: Upregulation of Expression of Nrf2 and Correlated Antioxidants Enzymes

The edible and medicinal part ofInula nervosaWall. (Xiaoheiyao) is confined to its root without sufficient phytochemical and biological investigation. In this study, the secondary metabolites of root, stem, leaf, and flower ofI. nervosaWall. were visualized using Global Natural Products Social Molecular Networking (GNPS), MolNetEnhancer, XCMS(xcmsonline.scripps.edu) analysis, and `ili mapping based on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) data to reveal their chemical differences. Among the 11 kinds of chemical repertoires annotated by MolNetEnhancer and 16 hits against the GNPS library, 10-isobutyryloxy-8,9-epoxythymol isobutyrate (1) was revealed as the most dominant and responsible marker between the roots and the other parts. Moreover, a battery of unique MS features as well as differential markers were discovered from different parts of the plant. The chemical differences contribute to the bioactivity differences, which presented in the 2,2-diphenyl-1-picryl-hydrazyl (DPPH)assay and H2O2-insulted HepG2 cells and were in significant correlations with the contents of1. real-time reverse transcription polymerase chain reaction (RT-PCR)results demonstrated thatI. nervosaWall. extracts upregulated the mRNA expression of nuclear factor E2-related factor 2(Nrf2), heme oxygenase 1(HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), manganese superoxide dismutase (MnSOD), and glutamate-cysteine ligase catalytic subunit (GCLC) actors involved in antioxidative response in H2O2-challenged HepG2 cells. These findings support the roots ofI. nervosaWall. as active parts ofXiaoheiyao, and also indicate the potential antioxidant activities of other parts.Keywords:Xiaoheiyao;GNPS molecular networking;MolNetEnhancer;XCMS online;Nrf2